Semiconductor multiple quantum well (MQW) infrared and thermal radiation imaging arrays are of considerable interest to military and commercial manufacturers because of their use in night vision and satellite applications.
Prior research on arrays made of solid state infrared detectors has concentrated on devices which incorporate semiconductor quantum well superlattices which are formed on semiconductor substrates. Typically, these multiple quantum well superlattice structures are designed such that within each quantum well there is a ground electron state and several energy bands and subbands defining excited electron energy states. Accordingly, when infrared energy is incident to the device, there is intersubband absorption which excites electrons from the ground state into one of the excited states. A measurable photosignal results when the photoexcited electrons tunnel out of the wells. Unfortunately, this type of design leads to devices which cannot be tuned very easily or which are difficult to manufacture within the required tolerances. Accordingly, there is always a need for alternative classes of infrared detecting devices. The present invention provides an alternate class of such a device array.